Cartons are often provided with a handle for convenient lifting and carrying. A satisfactory handle should be designed to be readily grasped, comfortable to the hand, and capable of lifting the carton without tearing. For cartons containing heavy loads, it has been common to reinforce the handle by making it of two-ply construction. For example, in fully enclosed sleeve-type cartons, the top panel often is formed by overlapping top panel flaps located at the ends of a blank. Each flap contains a handle opening arranged so that the top panel of the carton includes two spaced openings. This arrangement is sometimes referred to as a "suitcase handle" since the strap portion of the top panel between the handle openings is gripped in the manner of a suitcase handle. An example of such a suitcase handle can be found in the carton disclosed in U.S. Pat. No. 5,333,734.
U.S. Pat. No. 2,955,739 of Collura describes a handle carton in which a two-ply handle is attached to the end flaps of a carton and is positioned above the top panel of the carton. The two-ply handle is formed along the edge of the carton blank by folding and adhering one handle strip against another. The two-ply handle is then folded yet again in a "Z" fashion, causing the handle to be separated from the top panel of the carton, while still remaining attached to the end flaps.
Recently, larger and larger containers have been placed on the marketplace. When a large number of such larger containers are placed in a single carton, greater stress is applied to the traditional two-ply handle. To increase the strength of the handle, one could increase the board thickness of the carton blank. However, this has the disadvantage of increasing the cost greatly inasmuch as a significant portion of the cost of a finished carton is the cost of the raw material making up the blank. Furthermore, the cost of the blank is directly proportional to the thickness of the blank.
Accordingly, it can be seen that a need yet remains for a carton having an integral handle which has greater strength handle than known two-ply arrangements, while at the same time avoiding excessive costs. It is to the provision of such a carton that the present invention is primarily directed.